Research Paper Volume 14, Issue 19 pp 7734—7751

Figure 2. Oscillations of organ uptake, plasma clearance, and plasma levels of lipids during aging. Young (27–31 weeks old) and middle-aged (67–71 weeks old) female APOE*3-Leiden.CETP mice were injected with triglyceride (TG)-rich lipoprotein-like particles double-labeled with glycerol tri[³H]oleate and [¹⁴C]cholesteryl oleate at Zeitgeber Time 0 and 12 (n = 7–8 mice/group/time point) to assess [³H]oleate uptake by (A) interscapular brown adipose tissue (iBAT), (B) subscapular BAT (sBAT), and (C) perivascular adipose tissue (pVAT), and (D) [¹⁴C]cholesteryl oleate uptake by the liver, and plasma decay of (E, F) [³H]oleate and (G, H) [¹⁴C]cholesteryl oleate (n = 4–8 mice/group/time point). Fasted plasma levels of (I) TG and (J) total cholesterol (TC) (n = 7–8 mice/group/time point). (K) Oral lipid tolerance test performed at ZT12 with blood collection for plasma TG measurement, after which (L) the area under the curve (AUC) was calculated (n = 7–8 mice/group). Bar graphs and data points on curves represent means ± SD. ^*p < 0.05; ^**p < 0.01; ^***p < 0.001, according to unpaired t-test or two-way ANOVA and following Tukey’s multiple-comparison test.